Moving Forward on Indefinite Claims Could Haunt Petitioners
Often times when preparing an Inter Partes Review (IPR) petition, a claim is encountered that may be of an indeterminate scope under 35 U.S.C. 112. As indefiniteness issues are not considered in IPR, the question then becomes: Should the broadest of the possible competing construction for the claim term be proposed in order to get an IPR instituted on the claim? Or, should the petitioner avoid proposing a construction for an indefinite term to reserve rights for a later, district court challenge? Of course, holding back claims for a later district court proceeding is typically disfavored given the entire point of IPR, in most cases, is to avoid the expense of district court litigation. For that reason, most petitioners forge ahead to attack the indefinite claim.
In 2013, Sonix filed suit against a group of alleged infringers, and late in the case, based on the apparent realization that “visually negligible” could be considered a subjective term based on conflicting expert testimony, the defendants amended their invalidity contentions to newly-assert that “visually negligible” was indefinite, moving for summary judgment of indefiniteness.
In reversing the district court’s grant of summary judgment, the Court explained that, in addition to the written description, the post grant prosecution history also made reversal “compelling,” noting that “[n]o one involved in either the first or the second reexamination had any apparent difficulty in determining the scope of ‘visually negligible.’” Of course, much like IPR, patent reexamination precludes challenges based on indefiniteness, and examiners may not issue 112 rejections for original claim language.
The Court emphasized that during the first reexamination, the challenger “repeatedly argued that the prior art disclosed visually-negligible graphical indicators without any apparent uncertainty as to the meaning or scope of the term” and had no difficulty applying it to the references of record, and that during the second reexamination, the examiner “was able to understand and apply the term in performing a search for prior art and make an initial rejection.” (Note: reexamination typically does not entail searching as rejections are proposed in the request) The Court also noted that during the second reexamination the expert was able to understand this term sufficiently so as to differentiate between indicators which were (and were not) visually negligible, and the examiner was able to understand these opinions and differentiate between the indicators as well, resulting in withdrawing the rejection.
Although this case suggests that post-grant proceedings can be persuasive evidence regarding claim interpretation in district court proceedings, the Court was careful to note the limitations of its decision:
Our holding in this case does not mean that the existence of examples in the written description will always render a claim definite, or that listing requirements always provide sufficient certainty. Neither does the fact that an expert has applied a contested claim term without difficulty render a claim immune from an indefiniteness challenge. As always, whether a claim is indefinite must be judged “in light of the specification and prosecution history” of the patent in which it appears. Interval Licensing, 766 F.3d at 1369. We simply hold that “visually negligible” is not a purely subjective term and that, on this record, the written description and prosecution history provide sufficient support to inform with reasonable certainty those skilled in the art of the scope of the invention. The examiner’s knowing allowance of claims based on the term that is now questioned, plus the acceptance of the term by both parties’ experts, force us to the conclusion that the term “visually negligible” is not indefinite. Accordingly, we reverse the district court’s conclusion that the asserted claims are invalid as indefinite.
Although not a basis for the Sonix decision, keep in mind that the CAFC applied the Nautilus standard for indefiniteness rather than the stricter standard of the PTO. Nautilus is not as unforgiving as the analysis of the PTO (as pronounced in Ex parte Miyazaki and, more recently In re Packard (CAFC 2014). Given the PTO has a greater opportunity under Packard to reject terms under 112, this fact may also be raised to bolster PTO findings in similar fact patterns going forward. For this reason, troublesome terms are best noted in IPR petitions along with an explanation as to why 112 is not/cannot be raised.